Conventionally, in order to improve the dispersibility or the like of silica in a rubber composition for a tire containing silica, it has been proposed to use a silica which has been surface-treated with a silane coupling agent or the like (for example, JP 2012-172137 A).
However, the present inventors discovered that there is room for improvement in the rubber physical properties such as the modulus, fracture characteristics, low heat build-up (low rolling resistance), abrasion resistance, or impact resilience of rubber compositions for tires containing silica treated with silane coupling agents. The cause of this may lie in the fact that when the functional groups of a silane coupling agent react with rubber to form a bond, such a bond does not contribute to the stretching of the rubber.